Plain English Summary

Background and study aimsPatients with an underactive pituitary gland (hypopituitary) on replacement hormones but not growth hormone replacement have an approximately twofold increase in mortality, mainly due to diseases of the blood vessels (heart attacks, strokes). These patients show increases in body fat, reduced muscle mass, increased blood cholesterol, difficulties handling sugar, as well as increased levels of some clotting factors. How these latter observations translate to blocking of arteries and increased vascular disease is unclear. Blocking of arteries begins with inflammation of the lining, followed by accumulation of fat in the wall of the artery resulting in a localized plaque. Later clot formation on top of the inflamed fat-filled plaque blocks the artery. We aim to comprehensively characterize risk factors for blood vessel (vascular) disease in hypopituitary patients and study the process by which these risk factors translate into vascular disease. We also aim to determine whether growth hormone replacement can reverse any documented abnormalities. The study will include patients with an underactive pituitary gland who are deficient in growth hormone, and who wish to undergo a trial of growth hormone replacement.

Who can participate? Adults over age 18 years, and of either gender with confirmed growth hormone deficiency (GHD).

What does the study involve?The study involves measurement of height, weight, waist and hip circumference, and assessment of body fat and muscle content (electronic scale [bioimpedence] and absorptiometry [low dose X-rays]). Blood will be taken for a number of measures of blood fat, inflammation, sugar handling, factors that make the blood more sticky, and to examine the characteristics of clots that these patients form. A measurement of the thickness of the wall of blood vessels will be made with ultrasound (sound waves), and a blood pressure monitor worn for 24 hours. Once these tests have been performed the volunteers will be started on growth hormone and the dose optimised over three months. Patients will be left on the optimal growth hormone dose for three months and then all the tests repeated.

What are the possible benefits and risks of participating?There are no direct benefits to participating in the study. The data derived from the study will enhance our understanding of the risk of an underactive pituitary gland, how the observed abnormalities translate into vascular disease, and whether growth hormone can reverse the observed abnormalities. There are no significant risks associated with participating in the study. The dose of X-rays used in the absorptiometry scans is equivalent to the exposure received during half a day of normal background radiation from our surroundings.

Where is the study run from?The study is run from the Department of Endocrinology at Leeds Teaching Hospitals NHS Trust (UK).

When is the study starting and how long is it expected to run for?The study is expected to start in April 2013 and last three years.

Who is funding the study?Although the study is funded by Sandoz UK Limited, the study protocol and design is wholly the concept of Dr R Murray at Leeds Teaching Hospitals.

Primary contact

ORCID ID

Contact details

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

ED12/10391

Study information

Scientific title

Elucidation of the effects of growth hormone (GH) deficiency and GH replacement on vascular risk and clot dynamics

Acronym

Study hypothesis

Epidemiological studies support an increased vascular morbidity and mortality in growth hormone deficient (GHD) adults though do not prove cause and effect. We hypothesize that GH deficiency is associated with an inflammatory and thrombotic environment, which translates into the observed excess vascular mortality. Furthermore, we hypothesise that GH replacement will normalize the abnormalities in the inflammatory and thrombotic pathways.

Phase

Drug names

Primary outcome measure

Secondary outcome measures

Measurements will occur prior to commencing growth hormone replacement, and having been on a stable dose of growth hormone for three months. Measurement of body fat and muscle will be performed using an electrical scale (bioimpedence analysis) and X-ray absorptiometry. The latter uses low dose X-rays to differentiate between fat, muscle and bone. Levels of blood fats, sugar, clotting factors etc will be measured using standard laboratory assays. Rates of clot formation and breakdown will be assessed in the laboratory by measurements of changes in optical density using a spectrophotometer (measures changes in light) both at the beginning of the clotting reaction and after formation of the mature clot.

Overall trial start date

01/04/2013

Overall trial end date

01/04/2016

Reason abandoned (if study stopped)

Eligibility

Participant inclusion criteria

1. Able to give written consent2. Adults over age 18 years, and of either gender with confirmed GHD (insulin stimulation test <3 ug/L)3. Other hormone replacement therapy stable for at least three months